Messages in this thread | | | Date | Fri, 27 May 2022 08:25:42 -0700 | Subject | Re: [PATCH] drm/msm/dp: force link training for display resolution change | From | Kuogee Hsieh <> |
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On 5/26/2022 5:07 PM, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2022-05-26 10:26:18) >> During display resolution changes display have to be disabled first >> followed by display enable with new resolution. This patch force >> main link always be retrained during display enable procedure to >> simplify implementation instead of manually kicking of irq_hpd >> handle. > How is that better? Can you please describe how it improves things? I > suppose it avoids some round trips through the event queue just to turn > on the display?
This try to fix customer issues which only happen on one particular panel which fails on display resolution changes sometimes.
I will add more description.
> >> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> > Any Fixes tag? Or it's not fixing anything, just making things simpler? will add. > >> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c >> index 5ddb4e8..8b71013 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c >> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c >> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h >> index 2433edb..dcc7af21 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h >> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h >> @@ -20,7 +20,7 @@ struct dp_ctrl { >> }; >> >> int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl); >> -int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl); >> +int dp_ctrl_on_stream(struct dp_ctrl *dp_ctrl, bool force_link_train); > Can we have another API like dp_ctrl_on_stream_retrain()? Or name > 'force_link_train' to 'retrain'? > >> int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl); >> int dp_ctrl_off(struct dp_ctrl *dp_ctrl); >> void dp_ctrl_push_idle(struct dp_ctrl *dp_ctrl); >> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c >> index bfc6581..9246421 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_display.c >> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >> @@ -892,7 +892,7 @@ static int dp_display_enable(struct dp_display_private *dp, u32 data) > Any reason why dp_display_enable() is forward declared and why it takes > a u32 data argument? It's not part of the eventqueue calling code from > what I can tell so we should be able to rename 'data' to 'retrain_link'? > >> return 0; >> } >> >> - rc = dp_ctrl_on_stream(dp->ctrl); >> + rc = dp_ctrl_on_stream(dp->ctrl, data); >> if (!rc) >> dp_display->power_on = true; >> >> @@ -1594,6 +1594,7 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder) >> int rc = 0; >> struct dp_display_private *dp_display; >> u32 state; >> + bool force_link_train = false; >> >> dp_display = container_of(dp, struct dp_display_private, dp_display); >> if (!dp_display->dp_mode.drm_mode.clock) { >> @@ -1622,10 +1623,12 @@ int msm_dp_display_enable(struct msm_dp *dp, struct drm_encoder *encoder) >> >> state = dp_display->hpd_state; >> >> - if (state == ST_DISPLAY_OFF) >> + if (state == ST_DISPLAY_OFF) { >> dp_display_host_phy_init(dp_display); >> + force_link_train = 1; > Use true instead of 1 if the type is a bool please. > >> + } >> >> - dp_display_enable(dp_display, 0); >> + dp_display_enable(dp_display, force_link_train); >> >> rc = dp_display_post_enable(dp); >> if (rc) {
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